<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .outer{
            width: 500px;
            height: 300px;
            background-color: pink;
            text-align: center;
            padding-top: 200px;
        }
        .inner{
            width: 100px;
            height: 100px;
            background-color: green;
            margin: auto;
            line-height: 100px;
            
        }
    </style>
</head>
<body>
    <div class="outer">
        <div class="inner">
            inner
        </div>
    </div>
</body>
</html>